A known conventional junction box is shown in FIG. 5. The conductive portion is an electroconductive plate in flat body 1, the lower face of which is to be affixed to a vehicle. On the upper face, remote from the lower face, there is provided a plurality of fuse receptacles 2, a plurality of fuse holders, relay receptacles 3 adapted to receive a connector-integrated relay (not shown), and connector 4 for connecting the junction box to another circuit.
However, the foregoing construction has some disadvantages. Due to the fact that fuse receptacles 2, relay receptacles 3, and connector 4, must be arranged in the same plane, the whole body 1 is required to be large, and no reduction in size can be achieved. To attempt to miniaturize the junction box, it was thought advisable, for example, to make fuse receptacles 2 small and increase the density thereof, thereby reducing the area occupied thereby. However, such an arrangement makes it very difficult to replace the fuses and is, therefore, not desirable. Further, reducing the area of relay receptacles 3 is naturally limited by sizes of the relays.